Concept of a New Cylindrical Wind Turbine with Axial Inlet and Side Outlet Based on the Inverse Francis Principle

Abstract

This study presents a theoretical analysis of a cylindrical wind turbine concept featuring axial inlet and lateral outlet flow configuration. Inspired by the Francis water turbine principle operating in reverse (”inverse Francis”), we develop a mathematical model for particle-disc energy transfer and apply conservation laws to derive efficiency expressions. The analysis suggests that under idealized frictionless conditions, the inverse Francis configuration may enable high energy conversion efficiency. We propose a Wind-Eater Turbine (WET) design incorporating helically twisted blades, flow concentrator, and axial barrier. Unlike conventional horizontal-axis (HAWT) and vertical-axis (VAWT) wind turbines, the proposed closed-cylinder design operates as a semi-enclosed system where Betz’s limit derivation may not directly apply. Theoretical calculations indicate potential for efficiency exceeding conventional turbine limits, though experimental validation is required. Practical challenges including fluid viscosity, turbulence, and structural constraints are discussed. The work presents a conceptual framework for further investigation through computational fluid dynamics and physical prototyping.